myth or fact ?

N

nascarnhlnra

New member
I keep reading about 180 grain .40 's being more subject to kb's or headspacing issues. Is this something happening enough to really be concerned about or is this being exageratted ? I thought the 180 grain platform was what S&W designed the cartridge around to split the difference between the 9mm and the .45. I'm asking because I typically shoot more 180 grain than any other in .40 and carry 180 grain Hydra Shocks in my defense pistol ( A full size model ). I also hear alot about unsupported chambers and wish someone would explain in simple terms if this is evident in all pistols or just some. Sorry for the length but this has started to make me wonder and I'd rather be safe than sorry and ya'll are the folks I trust the most for info.:D
 
I'd just keep an eye on the OAL of any cartridge that gets rechambered, but then that's good to do with any caliber & bullet weight.
 
When I carried a G23 as a duty gun, I noticed the potential problem. It was caused by admin loading and unloading and the bullet would "settle" back into the case.

As I changed my carry ammo every month (every week now), never had a problem. However, in extreme circumstances (if one did not check his rounds), I believe it could kaboom.

Just MHO, not a gun mechanic. Don't fret, others here are.
 
Here's the way I understand the kB problem.
First, it is possble to have a catostrophic failure in any gun and any caliber. .40 S&W has been associated with the problem more than others as this is a high pressure round. Glock has also been identified as especially problematic. I do not know if this is true or not, but when you look at the factors contributing to the problem, I suspect it is so.
Unsupported chambers, excessive reloading of some cases, large amounts of lead in the rifling of barrels, bullets seated too far back and 180 gr bullets have all been associated with kBs. The Glock does have an unsupported firing chamber and has the kind of rifling that will hold onto lead more easily than standard rifling. The 180 gr. round supposedly leads to higher pressure upon ignition.
I have been using reloaded ammo in my Glocks for years, but always with jacketed bullets. I clean my arms after 200-300 rounds. I have seen no evidence in my rounds of bulging cases. Maybe I've just been lucky, but I think if you keep the rifling clean, don't use 'hot' loads, you will be ok.
If you are worried about it, if you always use new, factory ammo or switch to a supported barrel, you'll be fine.
I did switch to 155 gr ammo, not because of the possibilty of failure. I like the ballistics better on paper and I don't tire as easily from shooting the lighter loads. Less recoil, I think.
 
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